Ventilation grill for windows



FIG. 1 is a rear perspective view of a ventilation grill for windows showing my new design, with the butterfly valve in closed condition;

FIG. 2 is a rear perspective view thereof, with the butterfly valve in open condition;

FIG. 3 is an exploded rear perspective view thereof;

FIG. 4 is a front perspective view thereof with the butterfly valve in closed condition; and

FIG. 5 is a bottom plan view thereof, with the butterfly valve in closed condition. 

The ornamental design for a ventilation grill for windows, as shown. 